May 29, 2008 1300 UTC Day 1 Convective Outlook
Updated: Thu May 29 14:40:19 UTC 2008
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Public Severe Weather Outlook

The SPC is forecasting ...severe thunderstorms expected over parts of the central plains this afternoon and tonight....   Please read the latest public statement about this event.

Categorical Graphic
20080529 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20080529 1300 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20080529 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20080529 1300 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 291220
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0720 AM CDT THU MAY 29 2008
   
   VALID 291300Z - 301200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
   PORTIONS OF EASTERN NEB...WESTERN IA...AND EXTREME SOUTHEAST SD...
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF NORTHERN
   KS...CENTRAL NEB...CENTRAL IA...SOUTHEAST SD...AND SOUTHWEST MN...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE TX PANHANDLE TO
   SOUTHERN WI...
   
   ...REGIONAL OUTBREAK OF SEVERE THUNDERSTORMS AND TORNADOES EXPECTED
   TODAY OVER PARTS OF NEB/IA/SD...
   
   MORNING WATER VAPOR IMAGERY SHOWS A BROAD UPPER TROUGH OVER THE
   WESTERN STATES...WITH A BAND OF MODERATELY STRONG SOUTHWESTERLY MID
   LEVEL WINDS EXTENDING FROM THE FOUR-CORNERS INTO THE CENTRAL PLAINS.
    A WELL-DEFINED SHORTWAVE TROUGH IS NOTED OVER WESTERN CO.  THIS
   FEATURE WILL EMERGE INTO THE CENTRAL HIGH PLAINS BY EARLY AFTERNOON
   AND AID IN THE DEVELOPMENT OF INTENSE CONVECTION ACROSS PARTS OF
   KS/NEB/SD/IA.  STRONG SOUTHERLY LOW LEVEL WINDS ACROSS THE
   SOUTHERN/CENTRAL PLAINS ARE TRANSPORTING GULF MOISTURE RAPIDLY
   NORTHWARD AT AND ABOVE THE SURFACE.  DEWPOINTS APPEAR LIKELY TO
   CLIMB INTO THE MID-UPPER 60S OVER EASTERN NEB/WESTERN IA BY LATE
   AFTERNOON.  STRONG DAYTIME HEATING AND VERY STEEP MID LEVEL LAPSE
   RATES WILL COMBINE TO YIELD MLCAPE VALUES OF 2500-3500 J/KG.
   
   THUNDERSTORMS ARE EXPECTED TO INITIATE FIRST ALONG THE SURFACE
   DRYLINE OVER WESTERN NEB/KS BY MID AFTERNOON.  THESE STORMS WILL BE
   RATHER HIGH-BASED...BUT WILL LIKELY BE SUPERCELLULAR DUE TO STRONG
   DEEP LAYER VERTICAL SHEAR.  MORE STORMS ARE EXPECTED TO DEVELOP OVER
   THE WARM SECTOR IN EASTERN NEB/WESTERN IA DURING THE LATE AFTERNOON
   AND EARLY EVENING IN REGION OF RELATIVELY WEAK CINH AND STRONG CAPE.
    THESE STORMS WILL BE IN AN ENVIRONMENT OF LOWER LCLS...STRONGER LOW
   LEVEL VERTICAL SHEAR/HELICITY...AND MORE SUBTLE FORCING.  THESE
   FACTORS ARE EXPECTED TO RESULT IN A SEVERAL HOUR PERIOD OF DISCRETE
   SUPERCELLS CAPABLE OF VERY LARGE HAIL AND POTENTIALLY STRONG
   TORNADOES.  MODELS DIFFER ON PLACEMENT OF SURFACE WARM FRONT AND
   MOST LIKELY CORRIDOR OF SIG TORNADO THREAT.  HOWEVER...IT APPEARS AT
   THIS TIME TO EXTEND FROM ONL/GRI THROUGH THE SUX AREA INTO WESTERN
   IA.  LOW LEVEL WINDS AND VERTICAL SHEAR CONTINUE TO STRENGTHEN AFTER
   DARK IN THIS AREA WITH A SUSTAINED THREAT OF STRONG TORNADOES. 
   EVENTUALLY...ACTIVITY THAT DEVELOPED ALONG THE DRYLINE WILL SURGE
   INTO THIS AREA AND LIKELY ORGANIZE CONVECTION INTO A FAST-MOVING
   MCS.  AN ENHANCED THREAT OF WIDESPREAD DAMAGING WINDS IS EXPECTED TO
   DEVELOP ACROSS WESTERN/CENTRAL IA DURING THE EVENING.
   
   THE THREAT OF SIGNIFICANT SEVERE WEATHER APPEARS TO DIMINISH RAPIDLY
   SOUTH OF I-70 DUE TO WARMER MID LEVEL TEMPERATURES AND WEAKER DEEP
   LAYER SHEAR.  NEVERTHELESS...A FEW ISOLATED SEVERE STORMS WILL BE
   POSSIBLE ALONG SURFACE DRYLINE ACROSS THE OK/TX PANHANDLES INTO
   PARTS OF EASTERN NM,
   
   ..HART/JEWELL.. 05/29/2008
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z